I updated my Samsung Galaxy S8 to Android Oreo and ever since, my 4G LTE capabilities have been gone. When I am connected to wifi, the symbol displayed in the top bar is 1x. When I am off wifi, the most the connection ever goes to is 3G. I have tried restarting my phone but it has done nothing. I have tried turning mobile networks on and off but it has not helped. I have tried going on and off airplane mode, and all this does is return 4G LTE for about 15 seconds before it reduces to 3G every single time. This problem has only begun after the update because before, I know for a fact that my area has always had 4G LTE coverage and additionally, when on wifi, the 4G LTE symbol was always present in the top bar next to the wifi bars. How do I fix this??